Currently there exists a critical need within the military and homeland defense for sensors and detection systems that are capable of identifying and quantifying airborne microorganisms and biowarfare agents. In addition, monitoring of airborne particulates generated from industrial activities is a persistent concern within private and public settings. In general, bacterial and fungal spores are the predominant microorganisms that exist in air as aerosols. In order to reliably detect and identify small quantities of bioaerosols, a real-time detection system exhibits both high sensitivity and the ability to discriminate between potential threat agents and interfering substances present in the environment.
For a complete bioaerosol detection system, the four basic components are the trigger, collector, detector and identifier. The trigger determines a change in the particulate background and initiates operation of the remaining components of the system. The collector is a necessary component as the effective lethal dose of biological agents is extremely low (8,000-10,000 inhaled spores for Bacillus anthracis). The detector determines if the particulates are of biological origin, and the identifier specifically identifies the type of biological agent. Therefore, a real-time detection system includes both sampling/concentrating and identification in the same instrument.
An abstract published by Orono Spectral Solutions, Inc. entitled “Realtime Detection and Identification of Airborne Microorganisms Using Infrared Spectroscopy” discloses a detection system that couples an electrostatic precipitator for collecting airborne microorganisms with an infrared spectrometer for detecting and identifying the microorganisms.
An abstract published by Lynntech, Inc. entitled “Reagentless and Realtime Detection of Airborne Microorganisms” discloses a detection system that uses electrostatic precipitation to capture and preconcentrate biological agents and spores directly on a reusable infrared transparent crystal followed by infrared spectroscopic characterization.
U.S. Pat. No. 5,254,861 entitled “Biological Aerosol Particle Detector and Method Having an Electronic Pulse Detection Means” claims a system to detect airborne biological particles which first ionizes the particles with low energy radiation and then passes them between two electrically charged conducting plates. In one embodiment, an infrared laser diode and photodiode are added to characterize the biological particles based upon particle charge and drift velocity.
It would be desirable to provide an improved detection system for airborne particles.